The present invention relates generally to on-edge mounted slot-milling inserts and slot-milling tools comprising on-edge mounted slot-milling inserts.
In slot-milling cutters, the periphery of the milling body is equipped with a number of on-edge mounted slot-milling inserts, every second one of which protrudes in relation to one side of the toolholder and every second from the opposite side of the toolholder. The relative displacement of the slot-milling inserts is made in order to obtain clearance and in order to obtain slots having perpendicular or parallel bordering surfaces. The bottom surface of the slot is cut by the major cutting edges of the slot-milling inserts while the side surfaces of the slot are cut by the minor cutting edges extending substantially perpendicularly to the major cutting edges. Radii between the bottom surface and the side surfaces are obtained by means of more or less rounded cutting corners at a transition between associated pairs of major and minor cutting edges of each slot-milling insert. The relative displacement of the slot-milling inserts requires that the slot-milling inserts are formed in particular right hand and left hand embodiments in order to guarantee the requisite clearance between the side wall and the portion of the slot-milling insert following after the minor cutting edge.
It is desirable to provide an on-edge mounted slot-milling insert and a slot-milling tool wherein a single insert can be mounted on either side of a toolholder.
According to an aspect of the present invention, a slot-milling insert to be on-edge mounted to a toolholder of a slot-milling tool comprises a first side surface, a second side surface, and a plurality of edge surfaces between the first and second side surfaces, each edge surface intersecting with another edge surface at a corner and forming a cutting edge. The first and second side surfaces each have a side insert supporting surface for abutting against an abutment surface in a toolholder, and the insert has reflective symmetry about a central plane extending through the edge surfaces midway between the first and second side surfaces. A chipbreaker is provided on each edge surface and corresponds to each cutting edge, and each chipbreaker includes a recess beneath the cutting edge and a portion projecting toward the cutting edge, the projecting portion defining first and second chip deflecting recesses between the projecting portion and the first and second side surfaces, respectively.
According to another aspect of the present invention, a slot-milling tool comprises a toolholder, the toolholder having first and second sides and a peripheral surface between the first and second sides, the toolholder having at least two pockets, at least a first pocket of the at least two pockets extending inwardly from the first side and the periphery of the toolholder without reaching the second side of the toolholder, and at least a second pocket of the at least two pockets extending inwardly from the second side and the peripheral surface of the toolholder without reaching the first side of the toolholder. Each pocket carries an on-edge mounted slot-milling insert comprising a first side surface, a second side surface, and a plurality of edge surfaces between the first and second side surfaces, each edge surface intersecting with another edge surface at a corner and forming a cutting edge. The first and second side surfaces each have a side insert supporting surface for abutting against an abutment surface in a toolholder, and the insert has reflective symmetry about a central plane extending through the edge surfaces midway between the first and second side surfaces. A chipbreaker is provided on each edge surface and corresponds to each cutting edge, and each chipbreaker includes a recess beneath the cutting edge and a portion projecting toward the cutting edge, the projecting portion defining first and second chip deflecting recesses between the projecting portion and the first and second side surfaces, respectively.